Dresden 2014 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 45: Poster IV: One-Dimensional Metals: Reality or Fiction
DS 45.18: Poster
Donnerstag, 3. April 2014, 16:00–19:00, P1
Oxygen Adsorption on the In/Si(111) Nanowire Array: Structure and influence on metal insulator transition — •Stefan Wippermann1, Duck Mahn Oh2, Han Woong Yeom2, and Wolf Gero Schmidt3 — 1Max-Planck-Institute for Iron Research, Düsseldorf — 2Pohang University of Science and Technology — 3University of Paderborn
The ordered array of In nanowires that self-assembles at the Si(111) surface is an extremely popular model system for one-dimensional (1D) electronic systems. It exhibits an intriguing metal-insulator (MI) transition, that was recently shown to occur as a first order transition starting from condensation nuclei. While the nature of these condensation nuclei remains controversial, Oxygen has recently been observed experimentally to facilitate the metal-insulator transition.
Here we present density functional theory calculations to study the influence of O adsorption on the structural properties and the MI transition of the In/Si(111)-(4x1)/(8x2) nanowire array. We find three different low energy adsorption sites. However, a single oxygen adsorbed at any of these sites does not facilitate the phase transition. Instead, two oxygen atoms acting in concert catalyze the MI transition by lowering the energy barrier for the formation of 4x2 In hexagons. These in turn act as condensation nuclei for the MI transition.
S. Wall, B. Krenzer, S. Wippermann, S. Sanna, F. Klasing, A. Hanisch-Blicharski, M. Kammler, W. G. Schmidt, M. Horn-von-Hoegen, Phys. Rev. Lett. 109, 186101 (2012)